• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3309-3312
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• 2010

D-[$^{18}F$]FMAU and L-[$^{18}F$]FMAU are F-18 labeled nucleoside analogue which have been efficiently synthesized in order to be a PET imaging probe. D-[$^{18}F$]FMAU and L-[$^{18}F$]FMAU were compared as PET imaging agents using HSV1-TK gene expressing tumor-bearing mice. Their cellular uptake profiles were also compared using MCA and MCA-TK cell lines. D-[$^{18}F$]FMAU demonstrated higher cellular uptake and higher accumulation in MCA-TK tumor regions than L-[$^{18}F$]FMAU. On the other hand, L-[$^{18}F$]FMAU showed higher MCA-TK/MCA ratio of %ID/g than that of D-[$^{18}F$]FMAU. L-[$^{18}F$]FMAU can be utilized as a good candidate for HSV1-TK PET imaging. It can be used for antiviral drug evaluation.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.91-100
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• 2008

Ovarian cancer is often fatal since it is difficult to diagnose early and recurrence is quite frequent despite successful implementation of cytoreductive surgery and chemotherapy, thus exact diagnosis and early detection of recurrence are crucial to patient management. For pre-treatment staging, FDG PET could be helpful in a limited patient group possessing high risks of ovarian cancer. Besides, FDG PET could be recommended to patients with a high suspicion of recurrence i.e. rise of CA-125, especially in cases of conventional diagnostic imaging modalities presenting no evidence of disease because FDG PET provides critical information for treatment planning such as recurrence site or pattern. In order to expand the use of FDG PET to general population at staging or routine surveillance of ovarian cancer, more investigation is needed. The usefulness of FDG PET in evaluating treatment response and prognosis of ovarian cancer has not yet been determined, but it has been reported that FDG PET could evaluate treatment response early and show a close relationship with overall survival. PET/CT has been actively adopted in management of ovarian cancer. Not only in detecting tumor recurrence and evaluating treatment response but also in pre-treatment staging, FDG PET/CT is expected to playa role due to available anatomical information.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.60-65
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• 2008

Hepatocellular carcinoma is the most common primary tumor in the liver. FDG PET has been applied for staging and treatment planning of hepatocellular carcinoma. It could reflect tumor prognosis because glucose metabolism assessed by FDG PET is known to have correlations with the differentiation and aggressiveness of the tumor. Although the ability of FDG PET to detect well-differentiated or low grade tumors and intra-hepatic lesions is not good, it is expected to playa major role in pre-surgical assessments for liver transplantation because it is useful in detecting extra-hepatic lesions and unexpected distant metastases with a better diagnostic performance than other conventional imaging modalities. Additionally, FDG PET has an advantage to screen other cancers through whole body scanning. As a new tracer for PET, Acetate demonstrates higher sensitivity and specificity to FDG in evaluating hepatocellular carcinoma. It thus seems that simultaneous use of Acetate PET with FDG PET could be helpful in diagnosis, especially detecting extra-hepatic metastases.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.141-147
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• 2006

PET detects only less than 50% of early gastric cancer and 62-98% of advanced gastric cancer. Therefore, mass screening programs are recommended for all adults over the age of 40 for early detection and early treatment of gastric cancer through endoscopy or various radiological tests. The most important step after being diagnosed with gastric cancer is accurate staging, which mainly evaluates tumor resectability to avoid unnecessary surgery. Important factors that affect tumor resectability are whether the tumor can be separated from adjacent organs or important blood vessels, the extent of lymph node metastasis, presence of peritoneal metastasis, or distant organ metastasis. To evaluate the extent of local tumor invasion, anatomical imaging that has superior spatial resolution is essential. There are a few studies on prognostic significance of FDG uptake with inconsistent results between them. In spite of lower sensitivities for lymph node staging, the specificities of CT and PET are very high, and the specificity for PET tends to be higher than that for CT. Limited data published so far show that PET seems less useful in the detection of lung and bone metastasis. In the evaluation of pleural or peritoneal metastasis, PET seems very specific but insensitive as well. When FDG uptake of the primary tumor is low, the distant metastasis is also known to show low FDG uptake reducing its detection. There are only a few data available in the evaluation of recurrence detection and treatment response using FDG PET.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.193-198
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• 2004

PET/CT combines the functional information from a positron emission tomography (PET) exam with the anatomical information from a computed tomography (CT) exam into one single exam. A CT scan uses a combination of x-rays and computers to give the radiologist a non-invasive way to see inside your body. One advantage of CT is its ability to rapidly acquire two-dimensional pictures of your anatomy. Using a computer these 2-D images can be presented in 3-D for in-depth clinical evaluation. A PET scan detects changes in the cellular function - how your cells are utilizing nutrients like sugar and oxygen. Since these functional changes take place before physical changes occur, PET can provide information that enables your physician to make an early diagnosis. The PET exam pinpoints metabolic activity in cells and the CT exam provides an anatomical reference. When these two scans are fused together, your physician can view metabolic changes in the proper anatomical context of your body. PET/CT offers significant advantages including more accurate localization of functional abnormalities, and the distinction of pathological from normal physiological uptake, and improvements in monitoring treatment. A PET/CT scan allows physicians to measure the body's abnormal molecular cell activity to detect cancer (such as breast cancer, lung cancer, colorectal cancer, lymphoma, melanoma and other skin cancers), brain disorders (such as Alzheimer's disease, Parkinson's disease, and epilepsy), and heart disease (such as coronary artery disease).

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2646-2651
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• 2021

A rectangular-shaped PET system with an adjustable gantry (AGPET) has been developed for imaging small animals. The AGPET system employs a new depth of interaction (DOI) method using a depth dependent reflector patterns and a new digital time pickoff method based on the pulse reconstruction method. To evaluate the performance of the AGPET, timing resolution, intrinsic spatial resolution and point source images were acquired. The timing resolution and intrinsic spatial resolution were measured using two detector modules and Na-22 gamma source. The PET images were acquired in two field of view (FOV) sizes, 30 mm and 90 mm, to demonstrate the characteristic of the AGPET. As a result of in the experiment results, the timing resolution was 0.9 ns using the pulse reconstruction method based on the bi-exponential model. The intrinsic spatial resolution was an average of 1.7 mm and the spatial resolution of PET images after DOI correction was 2.08 mm and 2.25 mm at the centers of 30 mm and 90 mm FOV, respectively. The results show that the proposed AGPET system provided higher sensitivity and resolution for small animal imaging.

• Imaging Science in Dentistry
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• v.44 no.4
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• pp.325-332
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• 2014

A combination of positron emission tomography (PET) with $^{18}F$-labeled fluoro-2-deoxyglucose ($^{18}F$-FDG) and computed tomography ($^{18}F$-FDG-PET/CT) has increasingly become a widely used imaging modality for the diagnosis and management of head and neck cancer. On the basis of both recent literature and our professional experience, we present a set of principles with pictorial illustrations and clinical applications of FDG-PET/CT in the evaluation and management planning of squamous cell carcinoma of the oral cavity and oropharynx. We feel that this paper will be of interest and will aid the learning of oral and maxillofacial radiology trainees and practitioners.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.78-84
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• 2007

Quantitative analysis of dynamic brain PET data using a tracer kinetic modeling has played important roles in the investigation of functional and molecular basis of various brain diseases. Parametric imaging of the kinetic parameters (voxel-wise representation of the estimated parameters) has several advantages over the conventional approaches using region of interest (ROI). Therefore, several strategies have been suggested to generate the parametric images with a minimal bias and variability in the parameter estimation. In this paper, we will review the several approaches for parametric imaging with linearized methods which include graphical analysis and mulilinear regression analysis.

• The Korean Journal of Nuclear Medicine
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• v.37 no.1
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• pp.34-42
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• 2003

The dopamine transporter (DAT) is responsible for the re-uptake of dopamine from the synaptic cleft and is located on dopaminergic nerve terminals only. DAT single photon emission computed tomography (SPECT) and positron omission tomography (PET) imaging, therefore, offer the unique opportunity to study via striatal uptake the integrity of presynaptic dopaminergic nerve terminals in vivo. In recent years SPECT and PET using specific ligands binding to DAT have evolved as an useful tool for diagnosing and monitoring progression of neurodegenerative disorders affecting dopaminergic systems. This article briefly reviews the literature dealing with DAT SPECT and PET imaging in parkinsonism and other neurodegenerative disorders.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.257-262
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• 2006

Purpose: The standard protocol using large volume of oral contrast media may cause gastrointestinal discomfort and contrast-related artifacts in PET/CT. The aim of this study was to evaluate the usefulness of low dose oral contrast in $^{18}F-FDG$ PET/CT. Materials and Methods: We retrospectively reviewed the whole-body PET/CT images in a total of 435 patients. About 200 ml of oval contrast agent (barium sulfate) was administered immediately before injection of $^{18}F-FDG$. The FDG uptake of intestines was analyzed by visual and semi- quantitative method on transaxial, coronal and saggital planes. Results: Seventy (16%, 113 sites) of 435 images showed high FDG uptake (peak SUV > 4); 50 (74%, 84 sites) with diffuse and 20 (15%, 29 sites) with focal uptake. The most commonly delivered site of oral contrast media was small bowel (n=27, 39%). On PET/CT images, FDG uptake coexisted with oral contrast media in 26 patients (54%, 38 sites) with diffuse pattern and 9 (45%, 9 sites) with focal pattern, and by sites, those were 38 (45%) and 9 (31%), respectively. In small bowel regions, the proportion of coexistence reached as high as 61% (29/47 sites). A visual analysis of available non-attenuation corrected PET images of 27 matched regions revealed no contrast-related artifact. Conclusion: We concluded that the application of low dose contrast media could be helpful in the evaluation of abdominal uptake in the FDG PET/CT image.